Pseudotumoral Actinomycosis Mimicking Malignant Colic Disease: A Case Report and Literature Review

Abstract

Abdominal actinomycosis is a rare, chronic, and often unrecognized suppurative disease. It is caused by an anaerobic gram-positive bacterium, most commonly Actinomyces israeli. Colonic actinomycosis is rarely reported and may be responsible for a pseudotumoral syndrome leading, in the suspicion of malignancy, to a large and mutilating excisional surgery. It is usually the histopathological examination of the surgical specimens that accurately corrects the diagnosis. Here, we report a rare case of a colic actinomycotic involvement taking a pseudotumoral form. The diagnosis was made based on the pathological examination of the surgical piece. Intravenous and then adjuvant oral penicillin G treatment has allowed a favorable clinical evolution. This observation illustrates the preoperative diagnostic difficulties of this rare disease.

Keywords: Actinomycosis; Colon; Pseudotumoral syndrome.

Fig. 1

Irregular thickening of the descending colon with infiltration of the wall.

Fig. 2

Abscessed tumor of the left colon found during segmental carcinologic colectomy.

Fig. 3

a Numerous bacterial colonies found at the center of a fibrinous tissue. b Bacterial colonies with basophilic radiating filaments which are a key feature of actinomycosis.